In optical communications systems, optical interferometer devices are frequently used to filter and switch optical signals. Due to their compactness and suitability for mass production, waveguide-based interferometers are finding increased use. A carrier-injection waveguide interferometer may include two parallel p-n junctions disposed on, or proximate to, two corresponding arms of the interferometer. For best performance, it may be desirable to have balanced optical absorption in the two arms of the interferometer. However, manufacturing imperfections may result in a discrepancy in optical absorption between the two arms of the interferometer. This discrepancy can in turn translate into a reduced optical performance of the interferometer.
It is therefore desirable to provide a waveguide-based optical interferometer device that would be more tolerant to manufacturing imperfections.